(a) Field of the Invention
The present invention relates to an improved portable alarm system which is contained within a sealed housing and on which there is provided a key pad for temporarily adapting the alarm system to a particular lessee user and permitting the user to actuate or deactuate the control circuit within the sealed housing. The control circuit also transmits a user information code to a central control station to identify the source of the alarm signal.
(b) Description of Prior Art
Various portable alarms are known such as described, for example, in U.S. Pat. No. 3,551,906 which discloses an alarm circuit housed within a container which resembles a lunch box so that the alarm system is concealed or non-detectable. A clasp-type lock is mounted on the front wall of the cover to securely lock the cover in a closed position to prevent access to the interior of the container. However, if the lock is tampered with, the cover can be opened and the alarm disconnected. An on/off switch is located within the container and accessible when the cover is open. Accordingly, the alarm system can be tampered with.
U.S. Pat. No. 4,742,336 describes a very similar system and wherein the alarm is provided in a portable briefcase. The briefcase is also provided with hinges and latch elements and a lock to open the case whereby to remove intrusion detecting devices therefrom as well as the connecting electrical cords for the power and telephone lines. Another such type portable alarm is also described in U.S. Pat. No. 4,319,228. Again, the user has access to the circuitry and the alarm system can be tampered with.
Another disadvantage of these prior art devices is that a key is required for use of the device. If the key is lost or misplaced, the device cannot be utilized.